Electrolytic sanitiser generator

ABSTRACT

An electrically powered apparatus for generating a solute such as chlorine to sanitise a body of water such as a pool or spa, a by-product of such generation being an explosive gas such as hydrogen, said apparatus including: a) an electrolytic cell ( 1 ) adapted to operate in a substantially vertical orientation through a range of 45 degrees either side of the vertical; b) a water inlet ( 13 ) and outlet ( 14 ) both located at the lower end of said electrolytic cell ( 1 ); and c) a defined space ( 16 ) surrounding one or more electrodes ( 28 ) of said electrolytic cell ( 1 ), wherein, in, the event that water flow through said apparatus ceases and said electrolytic cell ( 1 ) continues to produce said explosive gas, said explosive gas will displace water in said defined space ( 16 ) until there is no water around said electrodes ( 28 ).

FIELD OF INVENTION

This invention relates to an electrolytic sanitiser generator.

BACKGROUND ART

The following references to and descriptions of prior proposals orproducts are not intended to be, and are not to be construed as,statements or admissions of common general knowledge in the art inAustralia or elsewhere.

Methods of electrolytic chlorination for the purpose of sanitisingwater, in particular, swimming pool and spa water have been disclosed.However, this invention is also applicable to other water sanitizingprocesses, such as involving water towers for air conditioning, andparticularly any other application that requires the addition of ahalogen sanitizer, such as chlorine, chlorine dioxide or bromine. Aneleotrolytic chlorine generator may involve the supply of low voltage DCpower to an electrolytic cell. Chlorine (or chlorine dioxide) isgenerated in solution with the relevant salts dissolved in water. Thewater containing the solute may be passed through the cell for thepurpose of sanitizing a body of water, such as a pool, spa or watertower.

It has been disclosed that by adding a specific amount of sodiumchloride to the body of water and providing an electrolytic cell poweredby a low voltage DC source in a filtration system, chlorine gas may beproduced in the cell and dissolved into the feed water. This process canbe used to effectively sanitize and treat the body of water. Although anadverse byproduct of this process is the production of hydrogen gasH₂(g), under normal operating conditions the H₂(g) flows with the feedwater into the body of water and escapes safely into the atmosphere.However, in some circumstances the water flow conditions may not benormal and it is at these times that safety issues arise with respect toH₂(g) containment. For example, a blocked suction line, closed valve(s),incorrect installation or a seized pump can effect a loss of water flow.It may also cause present safety devices to become ineffective,inoperable and/or redundant. In such circumstances, the cell maycontinue to produce H₂(g) such that the volume of H₂(g) contained in thesystem may reach dangerously explosive levels. The H₂(g) may continue tobe produced and fill not only the cell chamber but all the filtrationsystem plumbing and receptacles. A large H₂(g) reservoir may resultleading to a potentially explosive situation.

Electrolytic cells have been disclosed in which the electrodes arepositioned in between inlet and discharge ports of the cell with noprovision to trap and contain hydrogen gas in the event of a water flowstoppage. These cells are plumbed horizontally or vertically and may useflow switches plumbed in series with the cell to detect a water flowfault condition. In such an arrangement, the flow switch may be designedto suspend power to the cell to minimise the potential a H₂(g) build up.

The use of a flow switch may be considered a good primary safeguardagainst a loss of water flow. However, the use of a flow switch alone asa single safe guard against hydrogen gas build up has been found, in theinventor's experience, to be insufficient. A flow switch is a mechanicaldevice and therefore has a potential for failure. In the event of awater flow stoppage, a flow switch failure could cause a massivehydrogen gas volume to accumulate in the plumbing and filtrationequipment and therefore become hazardous. To the inventor's knowledgeand belief, this one safety device, which the inventor believes shouldonly be used as a primary measure, is the only safety feature reliedupon by electrolytic chlorinators currently on the market.

Cells have been disclosed having separate flow switches or integral flowswitches which operate at 90 degrees to the direction of flow. A cellmay be installed without plumbing the cell in a gas loop and where thecell is at the uppermost portion of the loop. In such an installation,an integral flow switch or a separate flow switch may be installed but afailure of the flow switch to detect a water flow failure could lead toa hydrogen gas is build up.

Other manufacturers have used a non mechanical conductive electrodearrangement positioned at the top of a horizontal cell chamber. However,such methods detect only the presence of water and not the flow ofwater. It may therefore fail to detect a lack of flow of water if thecell is not installed in the horizontal position as generally specifiedin installation instructions. Moreover, incorrect installation may findthe sensor positioned at the lower portion of the cell rendering iteffectively redundant. Incorrect orientation of the cell chamber maycause the inherent physical gas loop to no longer contain hydrogen gasin the event of a flow fault. If both return and suction line valves areclosed, the chlorinator cell will continue to operate. The inability ofthe hydrogen gas to displace the water in the cell may lead to apressure increase in the plumbing system and eventually damage theplumbing and potentially cause injury.

Chlorine generators vary greatly in design both with regard to theoperation of the power supply and cell design. Where a single polaritydirect current (DC) voltage is applied to the cell electrodes, regularacid washing to dissolve the calcium deposit from the electrodes may berequire. Where a DC voltage is applied to the electrode bundle andperiodically reversed, the calcium scale deposit may be dissolved toeffectively prevent calcium scale build up.

Reversing the polarity onto the electrode bundle to effectively keep theelectrodes free of calcium scale has been disclosed. One electrodebundle design previously described involves two electrodes on opposingends of the plurality of solid plate electrodes having opposingpolarity's. When a sufficient DC voltage is applied to the twoelectrodes and sufficiently saline water is passed through to permitelectrolysis, an opposing charge is induced onto the plate surface whichis parallel and in closest proximity. The other surface of this sameplate attains the opposing polarity and will induce an opposing chargeonto the next opposing plate surface and so on.

The electrode bundle effectively conducts the current through theplurality of electrode plates and the reaction to produce chlorine gason the anode faces of the plates occurs. This electrode bundle designdescribed is a bi-polar design and is used because it is compact. Abi-polar cell may operate as a single polarity system where acid washingis periodically required or when a specialised electrode coating isused. Thus the polarity may be periodically reversed to achieve the selfcleaning affect.

The efficiency of electrode bundles is compromised in three major ways:

(1) If the electrode bundle is poorly designed with insufficientphysical barriers positioned onto the electrode bundle, the currentleakage may be excessive and this compromises efficiency.

(2) If the power supply is poorly designed and the DC voltage appliedacross the bundle is too low, the efficiency is reduced. Efficient celldesigns have been disclosed, but their inability to operate at excessivesalt levels without compromise to efficiency and electrode life meanthat there is a need for a device which overcomes these difficulties.Manufacturer's salinity requirements vary but over salting of the bodyof water such as pool or spa water is a common problem. Where thesalinity level in, for example, a pool or spa is up to 85% greater thanthat recommended, the chlorine production efficiency and electrode lifetime may decline.

Using a power supply with a larger amperage capacity allows the cell todraw a larger current under excess salt conditions. This preventscurrent limiting devices from prematurely reducing the voltage to thecell (which would otherwise cause the inefficiencies in the cell).However, the excess current drawn by the electrode will compromise thelife time of the electrode and deliver more chlorine per hour thanofficially stated in technical or instruction manuals.

(3) If the salt level is higher than that required to operate the cellat 100% of the manufacturer's stated output, the increased cell load maycause the power supply to limit the current and, in effect, reduce thevoltage delivered to the electrode bundle. This may cause the powersupply to deliver a voltage of less than 4.0 volts per cell and the cellwill produce chlorine inefficiently. It will also fail to clean itselfeffectively upon polarity reversal and cause excessive current leakage,thus reducing the life time of the electrode bundle.

It is an object of the present invention to ameliorate or overcome oneor more of the disadvantages of the prior art or at least provide auseful alternative thereto.

STATEMENT OF INVENTION

Accordingly, in one aspect the invention provides an electricallypowered apparatus or generating a solute to sanitize a body of water,the apparatus including an electrolytic cell having a prescribed rangeof operational orientation outside which it is undesirable for theelectrolytic cell to operate; and a tilt switch mechanism associatedwith the electrolytic cell, wherein the tilt switch is adapted to switchoff power to the electrolytic cell when said electrolytic cell isorientated outside the range.

In another aspect, there is provided an apparatus for generation asolute to sanitize a body of water, a by-product of such generationbeing an explosive gas, the apparatus including an electrolytic cellhaving a prescribed range of operational orientation outside which it isundesirable for the electrolytic cell to operate; and a water inlet andoutlet both located at the lower end of said an electrolytic cell;wherein the range is the upright orientation of the electrolytic cellwithin 45 degrees to the vertical such that, in use, in the event thatwater flow through the apparatus ceases, the explosive gas will displacewater in the apparatus until there is no water in the electrolytic cell,whereby electrolysis and explosive gas production ceases.

In still another aspect the invention provides an electrically poweredapparatus for generating a solute to sanitise a body of water, aby-product of such generation being an explosive gas, said apparatusincluding:

-   -   a) an electrolytic cell operable only in a substantially        vertical orientation trough a range of 45 degrees either side of        the vertical;    -   b) a water inlet and outlet both located at the lower end of        said electrolytic cell; and    -   c) a defined space surrounding the electrodes of said        electrolytic cell,

wherein, in the event that water flow through said apparatus ceases andsaid electrolytic cell continues to produce said explosive gas, saidexplosive gas will displace water in said defined space until there isno water around or between said electrodes,

so that electrolysis and explosive gas production cannot continue andthe maximum accumulated volume of said explosive gas is substantiallyrestricted to that of said defined space.

In yet another aspect, there is provided a method of installing anapparatus as described above wherein the body of water is serviced by afilter and associated pump, the method including plumbing said apparatusin line and downstream of the pump and filter and orienting saidapparatus as close to vertical as possible.

In a particularly preferred arrangement, the apparatus includes anelectrolytic cell which is plumbed into a swimming pool or spafiltration system, downstream of an the other receptacles such as afilter or pump.

The apparatus may include one or more of the following:

a lower body chamber comprising a pool or spa water inlet and achlorinated pool or spa water discharge outlet;

an inner lower body water chamber to direct water flow through anupright electrode bundle column;

a bi-directional water flow by-pass valve contained within the lowerbody chamber;

an integral non mechanical bi-directional water by-pass port;

a bi-polar electrode bundle contained within the upright electrodecolumn;

an upright cell chamber;

a cell chamber end cap which seals the top of the upright cell chamberand contains the electrical termination points for one or more of thefollowing: the electrode bundle, a flow switch, a vertical cell levelswitch and one or more salinity/water sensors;

a locking ring to compress the end cap onto the cell chamber using ano-ring to form the water seal;

a stainless steel wire gauze to prevent debris from entering theelectrode bundle and is further prevent current leakage;

a lock nut to sealably join the upright cell chamber to the lower body;and/or

a pressure relief valve.

The apparatus includes a power supply, which might be mains AC, butpreferably includes a low voltage DC power supply. This may deliver avariable power On/Off duty cycle to the cell based on feed backinformation a computer processor such as a microprocessor associatedwith the power supply receives from the electrode bundle. Suchinformation may include salinity levels, water flow rate, water presenceand/or current draw.

The low voltage DC power supply may contain a transformer, rectificationdevice and a controlling microprocessor based printed circuit board(PCB) which controls the DC power modulation to the cell.

The apparatus is adapted to restrict the build up of hydrogen gas toless than 2 litres (L) through aspects of the physical design andelectronic safeguard of the apparatus.

The cell may contain a vertically operated flow switch, an omnidirectional cell level switch, conductivity sensors, an integralbi-directional water by-pass and/or a pressure relief valve. All thesemay combine with the vertical physical design of the cell to minimisethe hydrogen gas hazard and maximise safety. Even if the cell isinstalled incorrectly, back to front, upside down or the faultconditions as previously described in relation to the prior art exist,the inventive device described herein best ensures that the safetyaspects of the device are not compromised. A 2 L volume of hydrogen gasis considered safe in the water treatment industry and unlikely to leadto serious damage or injury.

The cell may be an electrolytic halide generating cell which contains anintegrated bi-directional water by-pass valve to ensure a regular flowto the cell, a water flow switch, a salinity/water sensor, a pressurerelief valve and an omni directional tilt switch for the purposes ofdelivering a halide sanitizer to a body of water in a safer manner thanis presently available.

The apparatus may include a chlorinator power supply that uses currentdraw information derived from the cell electrodes to modulate andcontrol power delivery to the cell. This current feed back modulationmay fully optimise cell efficiency and durability even if the salinityis higher than ideal.

The apparatus may dramatically minimise the horizontal plumbing spacerequired to accommodate an electrolytic cell. The improved safetyimplications of this will become apparent to the skilled person fromthis description.

The apparatus may also include a pressure relief valve within a lowerbody of the cell. The valve may be designed and located such that if theinlet and discharge ports of the cell are closed, all of the electronicprotection devices fail and the chlorinator continues to producehydrogen gas, the pressure relief valve may be adapted to open at 150kpa to 350 kpa, and preferably 200 kpa to 250 kpa. The relief valve willeffectively allow the increased pressure in the cell to force out thewater contained and resting in the lower body of the cell. Once thehydrogen gas has displaced the water in the cell, the water will bebelow the electrode bundle which will be unable to further producehydrogen gas.

In answer to the disadvantages of the aforementioned prior art inrelation to excessively saline water, the present invention may be ableto maintain the correct cell voltage even if the salinity level is up to85% greater than that which is recommended and beyond that normallyrequired to operate the cell at the predetermined chlorine outputmaximum. Under the present invention, in a preferred form, electrodelife may not be compromised as would be the case where an oversizedpower supply with excessive current capacity is inappropriately appliedand the electrode operating time is not reduced.

The apparatus may achieve this in a preferred form by including amicroprocessor to process current draw information obtained from theelectrode bundle. The current draw information may be directly relatedto the salt level in the water. If the current draw exceeds apredetermined maximum required for the cell to produce a publishedchlorine maximum, an On/Off duty cycle of the power delivery to the cellis altered so that the total chlorine production per hour is moderatedto correspond to the desired chlorine production rate. Accordingly, thecell may be switched off for a limited time thereby reducing overallchlorine production and extending electrode life.

Where the cell is intended to be installed in a vertical orientation,but is incorrectly installed at an angle of up to 45 degrees from thevertical, based purely on the physical aspects of the cell, thecontainment of hydrogen gas is limited to the volume of the cell chamberwhich is preferably less than 2.0 L (but not essentially, as in the caseof larger applications). However, it is considered that 2 L is arelatively safe contained gas volume. The inventive arrangement maytherefore allow for a large degree of orientation error. However, if theincorrect orientation of the cell exceeds an angle of 45 degrees fromthe vertical, the physical design alone of the inventive arrangement maynot contain the hydrogen gas in the chamber and may allow the hydrogengas to escape and fill the plumbing and receptacles in the system. Thismay result in the accumulation of a dangerously large reservoir ofhydrogen gas.

Advantageously therefore, a tilt switch mechanism may be provided on orin association with the cell for the purpose of limiting the potentialdevelopment of a dangerous volume of hydrogen gas in the event that thechlorinator cell is not installed vertically or in the recommended rangefor the particular application. The switch may suspend power delivery tothe cell and prevent the electrolytic reaction that produces thehydrogen gas by-product in the event that the cell is not installed inthe correct orientation as per installation instructions.

The tilt switch therefore further obviates hydrogen gas safety concernsassociated with incorrect cell installation and/or damaged or saggingplumbing. Where the apparatus includes a controlling microprocessor andassociated circuit, if the vertical cell chamber deviates from thevertical by a predetermined value over 45 degrees, the tilt switch willactivate causing the circuit to cut power delivery to the cell. Thisensures that hydrogen gas is not produced and forces the operator toinvestigate the cause of the failure and ultimately install the cell inthe correct orientation.

The tilt switch could be installed (e.g. retro-installed) in all cellhousing designs to improve the safety aspect of existing cellinstallations. The physical aspects of the upright cell of theinvention, however, provide the first safety feature. The tilt switchsafety mechanism augments the physical safety feature thus furtherlessening the likelihood that an excessive and dangerous hydrogen gasbuild up occurs.

The apparatus may include a water by pass within the lower body of thecell chamber. The by-pass may be bi-directional. In the event that waterflow cases and the augmentary flow switch fails, the correctly orientedcell will continue to generate hydrogen gas until it displaces the waterin the electrode chamber after which the production of hydrogen gasceases because it cannot be produced as the electrolytic process cannotoccur in the absence of the solution (water). This effectively limitsthe maximum production of gas to the volume of the chamber which istypically less than 2 L for standard (e.g. domestic) installations. Thedesign of the apparatus is such that even if the valve/s on the returnor discharge side of the chlorinator are accidentally closed, the gaswill still displace all the water in the cell and contain the gas in thecell chamber by permitting water to return to the feeder side of thesystem.

A separate bi-directional check valve may be provided which is plumbedas allow control mechanism in the by-pass leg of a salt chlorinatormanifold. To be most effective as a hydrogen gas containment aid andflow controller, the valve must provide for the bi-directional flow ofwater across the valve whilst controlling the water flow provided by thepump through the cell. The flow of water across the opening in thisby-pass assembly preferably allows enough water to flow through it inboth directions such that it is at least equivalent to the rate at whichthe hydrogen gas displaces the water in the cell chamber. The valve alsomay incorporate a tensioned valve which can be altered or set to openand allow the passage of water through it at a predetermined flow rate.

In a preferred form of the invention including a flow switch, if boththe suction line valves and the return line valves are accidentallyclosed such that a net water flow in any direction is not possible, theflow switch activates and ceases power delivery to the electrode bundle.However in its simplest form, the apparatus of the invention may operatewithout a flow rate control valve or check valve. The apparatus may beadapted to vary the power to, or the activity of, the electrolytic cellwhereby to regulate the rate of electrolysis.

The bi-directional water flow by-pass may be included within an internallower body manifold immediately below the cell. The integral by-pass mayserve two purposes:

(1) To deliver a predetermined water flow through the electrode chamberwhilst allowing excess water flow to by-pass the electrode chamber; and

(2) To prevent undesirable back pressure in systems where the flow ratemust high.

The by-pass allows for variable flow through the electrolytic cell andthe activity of the cell may be regulated by the microprocessor inresponse to variations in flow rate and other factors, such as salinityand water body selection (e.g. the spa or pool).

The by-pass valve may be a tension loaded valve. The by-pass valve maybe a check valve as discussed later. Whilst not totally preventing aby-pass of water, the tension loaded valve may allow for greater controlover the by-pass flow. The by-pass valve preferably does not operate asa positively closing check valve. A standard check valve allows water topass in only one direction. However, if a standard check valve isutilised and reliance is placed purely on the physical design of theinventive cell, a dangerous hydrogen gas build up could occur under someconditions as described previously, such as where the cell is installedat an orientation greater than 45 degrees to the vertical.

Yet another preferred feature of the inventive chlorinator cell is thesubstantially vertical or upright arrangement of the electrode bundleitself. The electrode bundle may be any suitable configuration and maycomprise multiple plates or other terminal or electrode features. Thebundle may be square or circular, oval or rectangular upright incross-section. The bundle may be squat shaped or elongate. Preferablythe bundle comprises between seven and nineteen plates.

Where there is a lower number of plates, the bundle may include aninsulator or flow regulator. The flow regular is preferably configuredto fill at least a cross-sectional area of the cell chamber not occupiedby the electrodes, for example centrally within the cell or, mosttypically, to one side. The flow regulator may offer resistance to waterflow which would otherwise be present with larger numbers of plates toensure sufficient time exposure to the bundle. The flow regulator maycomprise a bracket having one or more lateral portions in a plane normalto the direction of flow and the longitudinal axis of the bundle. It mayoccupy, in foot print, that portion of the electrode chamber notoccupied by the bundle. The lateral portion preferably has one or moreapertures to permit a limited flow of water therethrough and consistentwith the resistance electrode plates would provide if present in thespace occupied by the flow regulator.

The electrolytic cell may include an inner bi-polar electrode bundle.The bundle may be situated centrally or to one side within the cellchamber. The cell chamber may be any suitable configuration. It may becompact or elongate. It may be cylindrical, oval, square or rectangularin cross section. Preferably the cell chamber has an elongatecylindrical shape, square or rectangular section shape.

Water may be directed upwards by the by-pass assembly through theelectrode bundle chamber. After exiting the electrode chamber, the wateris redirected 180 degrees in a U-turn and flows vertically downwardsthrough an internal, preferably circumferential or annular, spacedefined by an outer chamber between the electrode bundle chamber walland an outer cell chamber wall. If the outer cell chamber wall is clearor transparent, the evidence of water flow or electrolysis occurringwilt be very easy to visually establish by the operator.

The electrode chamber may be connected to an end cap which may beremovable for replacement or service of the internal components of thecell. The inventive design allows the cell to be very compact whilstaddressing the hydrogen gas containment issues.

Another safety feature is that the direction of flow through the cellelectrode chamber could be reversed without jeopardising the safety ofthe arrangement as a result of incorrect installation.

The inventive cell may include a pressure relief valve in the lower bodychamber. In the event that both the inlet port and the exit port areclosed, and the electronic protection devices fail to detect the absenceof water flow and fail to suspend power to the cell, the pressure reliefvalve will open to allow the hydrogen gas to displace the water from thecell chamber which, when complete will effectively cause a cessation ofelectrolysis.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may therefore be better understood from the followingnon-limiting description of possible and preferred features of one ormore of the preferred embodiments of the invention. It is to beunderstood that the features illustrated in and described with referenceto the drawings are not to be construed as limiting on the scope of theinvention. In the drawings:

FIG. 1 is a perspective view of an electrolytic cell according to afirst embodiment having a full set of electrodes;

FIG. 2 is a transverse section through section A-A of the firstembodiment;

FIG. 3 is a transverse section through section B-B of the firstembodiment rotated 90 degrees relative to the view shown in FIG. 2;

FIG. 4 is the view of FIG. 2 showing the normal direction of flow ofwater through the system;

FIG. 5 is a transverse section of an electrolytic cell according to asecond embodiment having a small number of electrodes;

DETAILED DESCRIPTION OF THE DRAWINGS

In the drawings there is shown an apparatus including an electrolyticcell 1. The apparatus forms part of a swimming pool or spa filtrationsystem (not shown). The apparatus is plumbed downstream of all otherworking receptacles or components of the system, including the pump andfilter. The apparatus includes:

a vertical cell chamber 18;

a lower body 12 depending from the vertical cell chamber 18, the lowerbody 12 comprising a pool or spa water inlet port 13 and a chlorinatedpool or spa water discharge or outlet port 14;

an inner lower body water chamber 15 to direct water flow throughopening 4 to a vertical electrode bundle column 16 containing a bi-polarelectrode bundle 28;

a bi-directional water flow by-pass valve 17 mounted in the return sidewall of the lower body chamber 15;

a non mechanical bi-directional water by-pass valve port 21 integralwith the bi-directional water flow by-pass valve 17 or the lower bodychamber 15;

a cell chamber end cap 26 to seal the top of the vertical chamber 18 andto contain the electrical terminals 2,3 for the electrode bundle 28,flow switch 20, vertical cell level or tilt switch 22 and salinity/watersensors 23;

a locking ring 24 to compress the end cap 26 onto the cell chamber 18using an o-ring 25 to form a water- and gas-tight seal;

a stainless steel wire gauze 27 to reduce the amount of debris enteringthe electrode bundle 28 and to further reduce current leakage;

a lock nut 29 to sealably secure the vertical cell chamber 18 to thelower body 12;

a pressure relief valve 31 spring biased to closed position;

a printed circuit board (PCB) 33 on a panel 32 on which is also mountedthe omni-directional tilt switch 22.

The system also includes a low voltage DC power supply (not shown) whichdelivers a variable power On/Off duty cycle to the cell based on feedback information that the microprocessor associated with the powersupply receives from the electrode bundle 28 via the PCB 33. The panel32 includes 8 downward facing terminals (not shown) whichcorrespondingly make electrical contact with 8 upward extending pins 34to link the various sensory and operational components of the cell 1 tothe PCB 33.

The low voltage DC power supply fed in by electrical lead 35 contains atransformer and rectification device. It is controlled by themicroprocessor 33 based printed circuit board (PCB) which controls theDC power modulation to the cell 1. The present invention may be adaptedto restrict the build up of hydrogen gas to less than 2 litres (L) inthe system through aspects of the physical design and electronicsafeguards. An installation method may include installing the cell 1downstream of all the other filtration receptacles such as the filterand pump (both not shown).

The cell 1 is preferably installed such that the lower body 12 is placedin the plumbing line with the inlet port 13 and the outlet port 14horizontally positioned. Both ports 13,14 are preferably clearly markedto avoid incorrect directional installation, but if the cell 1 isinstalled back to front so that the inlet port 13 is connected to anoutgoing pipe, none of the safety aspects of the apparatus will becompromised.

Located within the lower body 12 is the inner lower body water chamber15. As shown in FIG. 4, this chamber 15 directs a proportion of theincoming horizontal water flow upwards in a vertical direction throughthe electrode bundle column 16 where, in operation, electrolysis occurs.

The lower body chamber 15 also contains the integrated bi-directionalwater by-pass valve 17. This spring assembly 17 is preferably preset topermit a predetermined proportion or certain flow rate of water toby-pass the cell 1 and the electrode bundle column 16. This effectivelyreduces the pressure drop across the cell assembly which is desirable inhigh flow applications.

The by-pass 17 may simply be an opening or series of openings by whichwater travels from within the internal by-pass chamber 15 and out intothe cell discharge line 14 without travelling through the electrodebundle chamber 16. The by-pass 17 contains an opening or series ofopenings 21 which are only partially blocked by the tension loaded valve17 which opens at a pre-determined flow rate.

The bi-directional water by-pass valve 17 can not totally restrict theby-pass of water and force all of the water flow through the electrodebundle column 16. The by-pass valve 17 is designed such that it onlyblocks a percentage of the aperture that is the by-pass valve port 21.The inner lower body chamber 15 therefore allows the water to flow fromthe inlet port 13 to the outlet port 14 or vice versa. This featureallows hydrogen gas generated by the electrolytic reaction to displacethe water in the cell 1 and to contain the hydrogen gas within the cellcolumn 16 in a safe volume in the event that the primary electronic flowswitch 20 fails to operate. The flow of water across the opening 4 inthis by-pass assembly must allow enough water to flow through the bodychamber 15 in both directions such that it is at least equivalent to themaximum rate at which the hydrogen gas displaces the water in the cellchamber 18.

The by-pass assembly of this preferred embodiment relies on theunencumbered passage of water in both directions across the valve 17 toeffect the safe and even displacement of water in both the electrodechamber for the bundle column 16 and the outer cell chamber 5 under allconditions of water flow failure. This physical aspect is notcompromised in that it is effectively failsafe and is effective as asafety measure in instances where other, perhaps primary, electronicprotection devices fail to act. In the event of a flow failure and thefailure of the primary electronic protection devices 20, 22 to act thebi-directional by-pass 17 allows the hydrogen gas to evenly displace thewater in both the electrode chamber 16 and the outer cell number 5. Thiseliminates contact of electrolyte with the gas producing electrodes 28thus ceasing hydrogen gas production. The gas produced will therefore belimited to the volume of the vertical cell chamber 16 which ispositioned over and above the horizontally upper-most section of thewater inlet 13 and the discharge port 14 located in the lower bodymanifold 12. The flow of water across the opening in this by-passassembly preferably allows enough water to flow through it in bothdirections such that it is at least equivalent to the rate at which thehydrogen gas displaces the water in the cell chamber.

The electrode bundle column 16 is located within the vertical cellchamber 18. The electrolysed water that passes through the column 16 isforced 180 degrees to a vertically downward direction in the annularspace of outer chamber 5 between the column 16 and the chamber 18.During electrolysis, the operator will be able to see the gaseousproducts of the reaction as the electrolysed water flows down throughthe annular space 5 and out through the discharge port 6 of the chamber18.

Positioned at the very top of the cell is the cell chamber cap 26 whichcontains the electrical terminals 2,3 for the electrode bundle 28, theflow switch 20, the omni directional cell level switch 22 and thesalinity/water sensors 23.

The integral flow switch 20 is positioned directly above the water exitarea 7 of the electrode bundle column 16. The flow switch 20 can beadjusted to switch on and activate the cell 1 at a specified flow rate.The flow switch 20 includes a doughnut-shaped magnet which moves upwardalong a hollow plastic shaft if sufficient water flows through the waterexit area 7 to displace the magnet from a resting position and activatethe flow switch 20. The hollow shaft contains a reed switch whichrecognises the position of the magnet. If the magnet is uppermost (i.e.corresponding to a high flow rate), the switch will close a circuit andthe power supply will deliver power to the electrode bundle 28 to effectelectrolysis of the water borne electrolyte.

The apparatus includes the vertical cell level or tilt switch 22 whichis capable of operating in any orientation such that it may be describedas omni-directional. This tilt or tip over switch 22 is wired and fittedinto the panel 32 such that if the cell chamber 18 is not verticallyupright when plumbed, the tilt switch 22, which will have apredetermined electrical contact break at a specific angle of less than45 degrees from the vertical, will activate to cut power to the cell 1.

The salinity/water sensors 23 are positioned in the upper portion of thespace 5 of the vertical cell chamber 18. The salty/water sensors 23include two sensor electrodes. The two electrodes test the salinitylevel periodically. The information is cross referenced with the currentpassing through, and the voltage of, the electrode bundle 28. Thisinformation is processed by the microprocessor in the power supply andthe determination of both the salt level and the electrode condition aremade and displayed on a display for the benefit of an operator. Processcalculations are made according to suitable algorithms to determine theamount of salt to be added and this may also be displayed if informationabout pool volume is programmed in by, for example, the operator. Thesalt level sensors 23 also act as another electronic flow-fail safetydevice. If the sensors 23 detect the absence of water (i.e.electrolyte), the power to the electrode bundle 28 will be cut and aflow fail indication will be displayed.

The power supply includes a feature which maximises the efficiency andlifetime of a typical bi-polar cell. The cell bundle 28 shown in thefirst embodiment has thirteen electrode plates all spaced atapproximately 2 mm apart and positioned parallel to one another. The twoouter plates 36 and the middle plate 37 are connected to the low voltageDC power source. Preferably, 28 VDC is used which in effect delivers 4.7VDC maximum per cell. However the person skilled in the art willappreciate that there are many variations on this arrangement wherebythe number of plates 38 and the amount of DC voltage may be varieddepending on the application, cost and space constraints. Indeed, inFIG. 5 there is shown all alternative second embodiment in which theelectrode bundle 128 contains only 7 plates 138. The flow rate of thesecond embodiment cell 101, compared to that of the full complement ofplates 38 (as shown in FIG. 2) is substantially the some because of theinclusion in the cell chamber 116 of one or more flow regulators 40. Theflow regulator 40 includes one or more lateral members 41 extendingacross the flow path which restrict flow, but permit some flow of theorder of that flow which would be permitted if footprint occupied by theflow regulator 40 were replaced by electrode plates 138. The flowregulator 40 is typically an integrally moulded plastic insert with anelongate member 42 extending the full length of the plates 138 and top,bottom, and intermediate lateral members 41 extending from the middleplate 137 to the outer wall 117 of the cell chamber 116. Apertures 43(which may vary in size and number depending on the application) in eachof the lateral members 41 provide the necessary conduit for flow throughthe area occupied by the flow regulator 41. Typically, the cells 1,101are square of rectangular in cross section normal to the longitudinalaxis and/or flow direction whereby the plates 38,128 may be of the sanewidth and the lateral members 41 may be square or rectangular and simpleto size and fit.

A electrode bundle 128 includes a seven plate or blade electrode bundle.The elongate member 42 of the plastic insulator 40 must be insertedalongside and up against the outer face of the exposed seventh electrodeand positioned centrally within the electrode column 116. This insulatesthe oater portion of this seventh plate and restricts the ability forthe face of same to take part in the electrolytic reaction. If the faceof the seventh plate was exposed, current leakage might increase andcell efficiency may decrease.

The area of the perpendicular barrier that affects the flow restrictionshould approximate the restriction to flow affected as if the remainingsix electrodes were in place. In general, the restrictive area wouldequate to between 2.0 to 10.0 cm2 and more particularly 5.0 cm2. Thisensures a consistent water flow through the electrode plates 128 whetherthere exists a thirteen-plate 28 or seven-plate configuration 128. Theinsulation barter 40 is not needed in the 13-plate configuration whenthe electrode bundle column 16 itself provides an effective insulationbarrier.

Manufacturers of pools or spas typically give installers advice as towhat is the preferred salinity level of the pool or spa water. Forvarious reasons, pool or spa water often has a resultant salinity higherthan that which is recommended. As a salinity overload safety feature,many chlorinator power supplies are current limited. This limits thecurrent draw of the cell and protects the power supply. A typicalchlorinator power supply has electronic circuits that will current limitor, in effect, reduce the DC voltage to the cell in order to control theamp draw of the cell.

The method by which power is supplied to a bi-polar electrode bundlearrangement such as in cell 1 is important in determining chlorineproduction efficiency, reverse polarity self cleaning efficiency andelectrode lifetimes. As a benchmark it is preferable to maintain DCvoltage at no less than 4.0 Volts per cell to optimise efficiency andelectrode lifetimes.

The delivery of power to the cell may involve the use of amicroprocessor in association with the low voltage DC power supply. Thisenables the processing of current draw and voltage information obtainedfrom the electrode bundle 28,128. The current draw information isdirectly related to the salinity level or conductivity of the water. Ifthe current draw exceeds the predetermined maximum required for the cell1,101 to produce the published chlorine maximum, the power on/off dutycycle will be automatically altered such that the chlorine productionrate per hour is maintained as per the stated output. Although thecurrent density may be greater at times when the salinity is higher thanrequired, the automatic duty cycle modulation ensures that in suchcases, the power ON portion of the cycle will be proportionately reducedand the OFF portion increased, ensuing electrode lifetimes are notcompromised.

In effect, if the salt level is at the predetermined recommended levelor if it is up to 85% in excess, the power delivered to the cell 1 overa 24 hr period will remain constant as will the chlorine output. Excesssalt levels over and above 85% of the recommended concentration willcause inefficiencies in the cell 1 to develop. An excess of salt to thisdegree would be highly unlikely. If, however, this does occur, analysisby the microprocessor would recognise this excess and the diagnosticdisplay on the power supply would recommend dilution of the water and/orthe microprocessor would switch off power to the cell 1,101.

Although the power supply must be designed to handle a higher currentthan may usually be provided, the increase in VA power of thetransformer need not be proportional to the maximum current increasedesired. If an excess salt level exists and a higher current is drawn bythe cell than is normally required to produce the published chlorineoutput per hour, the ON portion of the duty cycle is reduced and the OFFportion of the duty cycle is correspondingly increased. Because the dutycycle modulation is based on the current draw information obtained fromthe cell 1,101, the power output per hour of the power supply remainsconstant even if the salinity is up to 85% higher than normally requiredto achieve the stated maximum chlorine output. The automatic reductionin the ON time portion of the duty cycle if excess salt is presentobviates the requirement for the use of a proportionally larger VAtransformer than would normally be the case if this automatic duty cyclemodulation was not effected.

The preferred form of the invention may obviate the need to manuallytest the cell to determine the condition of the cell 1,101 and canprovide for means to incorporate testing means into the apparatus.Salinity is measured within the cell 1,101 via the sensors 23 and theinformation is processed and interpreted according to a knownrelationship of cell current draw verses salinity by the microprocessor.If the cell 1,101 draws a lower current than that which is anticipatedas per the relationship programmed into the microprocessor, anindication that the cell electrode bundle 28,128 is faulty will beilluminated on the display.

Many chlorinators presently on the market determine the salinity of thewater via the current draw of the cell only. This method, however, maycause the operator to over-salt the pool if the cell is faulty or is atthe end of it's life and draws a lower current.

The preferred form of the invention may also obviate the need tomanually switch the chlorinator cell 1,101 off to preventover-chlorination when the body of water being treated is reduced involume by a factor of up to 20 times. This typically occurs with acombined pool and spa where the chlorinator cell serves to treat bothpool and spa under normal filtration conditions. The body of waterassociated with the pool and spa combination is normally 50,000 L, thespa is typically only 1500 L. If the plumbing, for example by the use ofvalves, isolates the pool from the filter system so that the spa volumealone is being filtered, the chlorinator must switch off or operate at areduced output. Otherwise over chlorination will result. The preferredembodiments 1,101 recognise the heating of the spa via a flow switchplumbed into the spa suction line. In a pool and spa combination,generally the only time the spa suction is opened is when the spa isbeing heated and used. A flow switch in the spa suction line is used toprovide feedback to the microprocessor which controls the operation ofthe chlorinator that the spa heating or use cycle has begun. The flowswitch located in the spa suction line is activated so that themicroprocessor recognises this condition and the power to the cellchlorinator is switched off or reduced to a limited output level. Thisensures that the small body of water in the spa will not be overchlorinated.

The chlorinator cell 1,101 has a flow switch 20 associated with orconnected to it. When the flow switch 20 is activated (i.e. low or nowater flow through the cell 1,101), chlorine production is switched OFFor a reduced output mode is activated. The flow switch 20 is positionedin the cell 1,101 and relays information to the master control ormicroprocessor regarding the flow condition.

Generally when a pool pump (not shown) is starve of water, the waterwithin the pump will heat up and damage the pump. The apparatus caninclude, a pump protection monitor within the chlorinator cell 1,101which records the time or duration that the flow through the cell 1,101has ceased and, according to a preprogrammed time delay, will switch offboth the chlorine cell 1,101 and the pump. This protects the pump frommiming dry and damaging itself.

Any auxiliary device/s may also be operated from the microprocessor ofthe chlorinator cell 1,101 and may be protected in the same way as thepump as described above.

For example, the apparatus can include a first and a second time clock.The second time clock within the microprocessor or chlorinator may beused to control a second pump which may be used to regulate theoperation of a pressure-type pool cleaner. In this case, a flow sensor20 located within the cell 1,101 aid positioned on the return linedownstream of all of the other equipment in the filtration system, willdetect when flow ceases. The pressure pump used to operate the cleanerrequires the primary filter pump to be operating correctly to providewater to the pressure pump. If the filter pump is switched off or isbeing used to backwash the filter, water flow on the return line ceasesand the pressure pump will be starved of water thereby damaging it if itis not switched off. This arrangement obviates the need to manuallyswitch the pressure pump off. Via the flow switch 20, the processorswitches the pressure pump off during any period in which it detects noflow.

Under prior art regimes, the operator must manually test the salt levelby means of a conductivity test apparatus or chemical test. Once thesalt level is established, a manual calculation of the salt requirementis performed using a table. This table lists the amount of salt requiredto raise a volume of water to a specific salinity. In the presentarrangement, assuming the correct water body volume has been recorded byinput into the microprocessor, the microprocessor is adapted to indicateto an operator, via the display, how much salt to add to correct anydeficiency in the level of water salinity.

The salt sensors 23 within the cell column 16 inform the microprocessorof the level of salinity of the body of water and reference thissalinity level to the target salinity which is recommended by themanufacturer.

The operator/installer must program into the chlorinator 1,101 the waterbody (such as pool) volume. The microprocessor is then able to calculatethe salt deficiency based on known formulae and to display therecommended salt addition required to correct this deficiency.

The substantially vertical or upright cell design allows the entire cellassembly to be installed in a plumbing circuit using a total of 190 mmof pipe space. No other cell presently available can be installed in aplumbing circuit where only 190 mm of plumbing space is available. Manycells presently available use approximately 225 mm to 400 mm of plumbingspace. The facility for the inventive cell to be fitted into limitedplumbing space has inherent safety implications.

Salt chlorinator installation instructions, independent of the design,should always insist that the cell installation be downstream of all ofthe other filtration system receptacles. This ensures concentratedchlorine produced does not corrode heaters, for example. It also helpsto eliminate the possibility of a dangerous volume of hydrogen gasaccumulating in the filter bowl or the solar heating system or any otherreceptacle where accumulation of in excess of 2.0 L of gas may occur.

It is the inventor's 20 years experience in this field that has shownthat instructions are not always followed by the installer if adheringto them requires more time and effort. It is a re-occurring theme thatinstallers of these devices find the large space required by some of thepresently available chlorinator cells particularly difficult to fit,especially in retro-fit applications. If the installer does not fullyappreciate the implications of installing the cell upstream of all theother filtration equipment receptacles, he may install it upstream ifthe plumbing more easily allows for it. Because the electrolytic cell 1disclosed herein uses only 190 mm of plumbing space, the likelihood offinding a satisfactory area downstream of the other receptacles isgreater.

EXAMPLE

If the tested salinity is 2000 ppm, the pool volume is 45,000 L and thetarget salinity is 2500 ppm, the chlorinator 1 will display a requiredsalt addition of 22.5 kg to rectify the deficiency.

UTILITY OF INVENTION

There is no practical way of ensuring that the cell is installed in thecorrect downstream position of the plumbing system thus preventing thepossibility of a hydrogen gas accumulation in the equipment receptacles.The preferred cell arrangement, however, has inherent physical designand electronic features to safely control the hydrogen gas production ifthe cell is not installed vertically or a flow fail condition occurs.These features are not negated if the cell is installed upstream of theother equipment receptacles in the system and the likelihood of ahydrogen gas accumulation occur in one or more of the other receptaclesis greatly reduced.

Throughout the specification, including any claims, the word “comprise”and its derivatives are intended to have an inclusive rather thanexclusive meaning unless the context requires otherwise.

It will be appreciated by those skilled in the art that manymodifications and variations may be made to the embodiments describedherein without departing from the spirit or scope of the invention.

1. An electrically powered apparatus for generating a solute to sanitisea body of water, a by-product of such generation being an explosive gas,said apparatus including: a) an electrolytic cell operable only in asubstantially vertical orientation and through a range of angles eitherside of the vertical up to a predetermined maximum angle, the maximumangle being 45 degrees or less; b) a water inlet and outlet both locatedat the lower end of said electrolytic cell whereby no water canpermanently collect above the base of the electrodes of saidelectrolytic cell; and c) a defined space surrounding said electrodes ofsaid electrolytic cell, wherein, in the event that water flow throughsaid apparatus ceases and said electrolytic cell continues to producesaid explosive gas, said explosive gas will displace water in saiddefined space until there is no water around or between said electrodesthat would enable electrolysis and explosive gas production to continueand the maximum accumulated volume of said explosive gas issubstantially restricted to that of said defined space.
 2. An apparatusaccording to claim 1, further including an orientation responsive meansto switch off power to said electrolytic cell when said electrolyticcell is orientated outside said range of angles.
 3. An apparatusaccording to claim 15, wherein said orientation responsive means is atilt switch associated with said electrolytic cell, said tilt switchbeing adapted to prevent delivery of power to said electrolytic cellwhen said electrolytic cell is orientated outside said range of angles.4. An apparatus according to claim 16, wherein said tilt switch is wiredand fitted into said electrolytic cell, wherein if said electrolyticcell is not vertically upright when plumbed, said tilt switch, whichwill have a predetermined electrical contact break at a specific angleof less than 45 degrees from the vertical, will activate to cut power tosaid electrolytic cell.
 5. An apparatus according to claim 1, furtherincluding a lower chamber incorporating said inlet and said outlet. 6.An apparatus according to claim 1, further including a bi-directionalwater flow by-pass means in said lower chamber to cause a portion of thetotal water flow to by-pass said electrolytic cell by passing directlyfrom said inlet to said outlet, wherein said by-pass means regulateswater flow to said electrolytic cell, allowing excess water flow toby-pass said electrolytic cell.
 7. An apparatus according to claim 6,wherein said integral by-pass serves two purposes: (1) to deliver apredetermined water flow through an electrode chamber defining saiddefined space whilst allowing excess water flow to by-pass saidelectrode chamber; and (2) to prevent undesirable back pressure insystems where the flow rate is or must remain high.
 8. (canceled)
 9. Anapparatus according to claim 7, wherein said apparatus includes achlorinator power supply that uses current draw information derived fromsaid cell electrodes to modulate and control power delivery to saidelectrolytic cell to fully optimise cell efficiency and durability evenif the salinity is higher than ideal.
 10. An apparatus according toclaim 7, further including a salinity sensor adapted to communicate datato a microprocessor associated with said electrolytic cell, saidmicroprocessor operable to regulate the operation of said electrolyticcell.
 11. An apparatus according to claim 7, further including a currentdraw sensor adapted to communicate data to a microprocessor whichresponds to said data to regulate the operation of said electrolyticcell.
 12. An apparatus according to claim 9, wherein said current drawinformation is directly related to the salt levels in the water suchthat if the current draw exceeds a predetermined maximum required forsaid electrolytic cell to produce a published chlorine maximum, anOn/Off duty cycle of the power delivery to said electrolytic cell isaltered so that the total chlorine production per hour is moderated tocorrespond to the desired chlorine production rate.
 13. An apparatusaccording to claim 6, wherein said by-pass means comprises abi-directional check valve, wherein said check valve provides for thebi-directional flow of water across said check valve whilst controllingthe water flow provided by a pump through said electrolytic cell, theflow of water across the opening allowing enough water to flow throughit in both directions such that it is at least equivalent to the rate atwhich the hydrogen gas displaces the water in the electrode chamber. 14.(canceled)
 15. An apparatus according to claim 1, further including aninner bi-polar electrode bundle comprising between seven and nineteenelectrode plates.
 16. An apparatus according to claim 2, furtherincluding: d) a cell chamber housing said electrolytic cell and definingsaid defined space, whereby said cell chamber defines a passage for thein-flow of water from said inlet; and e) an outer chamber, housing saidcell chamber whereby an outer space is defined between the outer surfaceof said cell chamber and the inner surface of said outer chamber, theouter space serving as a return passage for outgoing water which hascome from said electrolytic cell and is heading for said outlet.
 17. Anapparatus according to claim 13, further including a pressure reliefvalve in said lower chamber, wherein, in the event that both said inletand outlet are closed and augmentary electronic protection devices failto detect the absence of water flow and fail to suspend power to saidelectrolytic cell, said pressure relief valve will open to allow thehydrogen gas to displace the water from said cell chamber which, whencomplete, will effectively cause a cessation of electrolysis.
 18. Anapparatus according to claim 1, further including a flow switch todetect the absence of water flow through said apparatus, whereby saidflow switch is adapted to effect the cutting of power to said apparatusif the water flow reaches an unsustainably low rate.
 19. (canceled) 20.An apparatus according to claim 1, wherein where there are less than afull complement of electrode plates necessary to fill said definedspace, the defined space contains an insulator and flow regulatorconfigured to fill at least a cross-sectional area of said defined spacenot occupied by the electrodes, whereby to provide resistance to waterflow which would otherwise be present with the full complement ofplates, the arrangement being effective to ensure sufficient timeexposure of the flowing water to said electrodes.